1. Technical Field
The present invention relates to an apparatus for supplying gas to inflate a vehicle occupant restraint, such as an airbag, and particularly to an apparatus for supplying generated gas along with stored gas. Description of the Prior Art
Typically, an inflatable vehicle occupant restraint is inflated solely by gas which is generated by ignition of gas generating material. The gas generating material is generally volatile and must be handled carefully. Some have suggested that inflatable restraints be inflated by gas which is stored under pressure and by gas which is generated through ignition of gas generating material. In this way, the amount of gas generating material used can be reduced
U.S. Pat. No. 3,723,205 discloses an apparatus for supplying gas to inflate a vehicle occupant restraint. The apparatus comprises gas generating material in combination with stored pressurized gas. The stored gas can be nitrogen, air, carbon-dioxide or helium. The gas generating material, when ignited, generates a hot gas. The gas generating material comprises a halogen free alkali metal salt, an inorganic oxidizer, and a polyvinyl chloride binder. Suitable inorganic oxidizers include alkali metal chlorates and perchlorates, such as ammonium perchlorate, and alkaline earth metal nitrates. Examples of halogen-free alkali metal salts are alkali metal oxalates, carbonates, bicarbonates, and azides, e.g., KN.sub.3, The generated gas ruptures a seal and is directed into the pressurized stored gas. This increases the temperature and thus the pressure of the stored gas causing the commingled stored gas and generated gas to rupture a second seal. The commingled gas then flows into an inflatable device.
In U.S. Pat. No. 3,723,205 the ignition of the gas generating material creates relatively small particles which flow with the gas directly into the inflatable device. Removing these relatively small particles apparently was considered unnecessary because the patent does not disclose a technique for removal of these particles.